1. Field of the Invention
The present invention relates to gas lighting rods.
2. Description of Related Art
A gas lighting rod is a wand-like device used for lighting fires, comprising a source of gas and an operating member which, when manually pressed down, opens a gas flow path to the end of the device and, by means of a piezo-electric element, generates a spark for igniting the gas. The operating member is spring-loaded to return to its normal; position after operation. Various examples are described, for example, in U.S. Pat. No. 5,697,775 (Tokai).
It is important to provide a safety mechanism, to reduce the chances of the device being operated by children. The standard safety technique is to provide a spring-loaded safety member which has to be operated before the operating member can be operated; the safety member can be moved transversely to the operating member to release the operating member. The operating member moves generally longitudinally along the axis of the lighting rod, and the safety member thus moves transversely to the axis of the lighting rod.
We have found that this relationship, between the operating and safety members has significant disadvantages. The application of a high force on the operating member is liable to cause distortion of the safety member such that the operating member becomes freed and can therefore move and cause ignition. The spring force on the safety member needs to be limited in order to limit friction with the operating member; if the spring force is too high, when die safety member is released and the operating member is operated, the latter may be blocked in an intermediate position. Further, in such an intermediate state or position, the operating member may not return fully to its normal position, so holding the safety member in the release position; the operating member can then be operated without the safety member having to be operated first to release it.
According to die invention there is provided a gas lighting rod comprising a gas release valve and a piezo-electric lighting system both operated by a spring-loaded operating member, and a spring-loaded safety member which has, to be operated to release the operating member, characterized in that the operating member is aligned transversely and the safety member comprises a pivoted lever having a lock/release arm extending generally along the axis of the operating member and interacting therewith and a control arm engaged on the other side of the pivot and from the opposite side of the lighting rod from the operating member.
The end of the lock/release arm is preferably sloped such that its engagement with the operating member tends to urge it into the locked position if the user attempts to operate the operating member without first fully operating the safety member. This arm is also preferably substantially enclosed within the operating member.
The spring force provided by the piezo spring may be enough to provide the required spring bias to the operating member so that an additional biasing spring for the operating member is not required.
This arrangement has various structural advantages. The fact that the lock/release arm is substantially enclosed within the operating member means that even under the application of an extremely high force on the operating member, the safety member will remain effective to restraint movement of the operating member. The spring force on the safety member can be adjusted within wide limits without resulting in undue friction with the operating member. Further, the system is virtually immune to the safety member taking up an intermediate state or position in which the operating member can be operated a second time without having to operate the safety member, as the safety member is biased from such a potential intermediate position towards the correct position.
The arrangement also has the functional advantage that it is particularly easy and comfortable to operate. It can readily be held in the hand in such a way that the users thumb falls comfortably onto the operating member on one side of the lighting rod and their forefinger on the control arm of the safety member on the opposite side (or possibly vice versa). In contrast, in the prior art designs, the longitudinal arrangement of the operating member and the transverse arrangement of the safety member can make operation of the lighting rod awkward and inconvenient.